CHAPTER 15: GASES

Question 1

properties of gases

Answer 1

● Low density
● Fill entire space available
● Can be compressed easily
● Mix together rapidly

Question 2

kinetic molecular theory

Answer 2

● Gases are composed of small particles (atoms or molecules)
● The volume of the particles in a gas is very small compared with the volume
they occupy (most of the volume of a gas is empty space)
● Gas particles move rapidly in random, straight lines
● Particles collide with each other and with the walls in which they are contained
● The intermolecular forces between gas particles are very weak
● Average kinetic energy of gas particles increases as the temperature of the
gases increases

Question 3

partial pressure

Answer 3

Each gas exerts its own partial pressure when it collides with the walls of a container

Question 4

kelvin scale

Answer 4

As temperature decreases, the kinetic energy of the gas particles decreases

At -273 °C, the particles are not moving = zero kinetic energy

-273 °C = 0 K (kelvin)

Kelvin is a unit to measure temperature. Zero kelvin is considered absolute zero (when molecular motion stops)

Question 5

standard lab conditions

Answer 5

● At SLC, most gases behave like an ideal
gas and have a similar molar volume to
an ideal gas

● Ideal gas: a theoretical gas in which there
are no intermolecular force between the
particles

Question 6

how pressure affects volume

Answer 6

● Changing the volume of a fixed amount of gas at a constant temperature changes gas pressure

● The volume of the gas is inversely proportional to its pressure.

Question 7

molar volume of gases

Answer 7

• the volume occupied by 1 mole of gas at a particular pressure and temperature
• 1 mole of ALL gases has the same molar volume
• molar volume changes w temp and pressure
• Equal amounts, in moles, of different gases occupy equal volumes when measured at the same temperature and pressure